Detectophone.



J. E. B. HOLLADAYJ DETECTOPHONE.

APPLICATION nuzo AUG.22. 1913.

1 1 86,3 98 Patented June 6, 1916.

THE COLUMBIA PLANOGRAPH co WASHINGTON D C UNITED STATES PATENT onnion.

JOSEPH E. B. HOLLADAY, OF SUFFOLK, VIRGINIA, ASSIGNOR TO THE HOLLADAYDETECTO COMPANY, INC., VIRGINIA.

OF SUFFOLK, VIRGINIA, A CORPORATION OF DETECTOPHONE.

Application filed August 22, 1913.

To all whom it may concern Be it known that I, JOSEPH E. B. HOLLA- DAY,a citizen of the United States, residing at Suffolk, in county ofNansemond and State of Virginia, have invented certain new and usefulImprovements in Detectophones, of which the following is aspecification.

This invention relates to an improvement in detectophones, whichconsists of an apparatus which may be placed in a room and theconversation between individuals occupying the room can be distinctlyand clearly heard in another room on the same floor of the building, orin another room at practically any distance therefrom.

The invention consists of certain novel features of construction andcombinations of parts which will be hereinafter described and pointedout in the claim.

In the accompanying drawing, I have disclosed a diagrammatic view,setting forth a system of wiring connecting the battery, transmitter,receiver, and induction coil.

As set forth in the drawing, the battery B has wires 0 and f leadingtherefrom, the wire 0 leading to the contact terminal as, and the wire fleading to a binding post A. A wire C leads from the binding post A tothe receiver R, and thence to the transmitter T. The switch S has a wire9 leading to the binding post B, and a wire d leads from the bindingpost A to the transmitter. An in duction coil IC has a wire 7' leadingto the binding post A, and a wire 9 leading to the wire 9, so that theprimary coil of the induction coil is connected to the battery circuitupon the switch S being thrown into contact with the contact terminal asby the knob y. A wire it of the secondary coil is connected to the wireg.

Specification of Letters Patent.

Patented June 6, 1916.

Serial No. 786,140.

With the use of this apparatus or system, the transmitter can be placedin a room and concealed, if desired, and the receiver and otherapparatus, such as the battery and induction coil, can be placed inanother room in any part of the building desired, and by placing thereceiver to the ear, the conversation taking place in the room in whichthe transmitter is locatedcan be distinctly heard and the voices of theconversationists recognized.

With such an apparatus the uses are practically unlimited, as forinstance, it can be used in detecting the persons operating illegalhouses, such as gambling dens and the like, as persons entering theseplaces can be recognized by their voices, and their entire conversationheard by the person holding the receiver, and the stenographer, forinstance, who has the receiver, can take down stenographically theconversations taking place.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent is:

A telephone system comprising a two wire circuit, a receiver andtransmitter arranged in series in said circuit, an induction coil theprimary winding of which is connected in shunt across the main circuit,while the secondary coil is connected in shunt with one of said wires ofsaid main circuit, and a switch interposed between the main circuit andthe shunt circuit.

In testimony whereof I aflix my signature, in the presence of twowitnesses.

JOSEPH E. B. HOLLADAY.

Witnesses:

EMILY F. CAMP, WATTS F. ,ESTABROOK.

Copies of this patent may be obtained for five cents each, by addressingthe "Commissioner otlatents,

Washington, D. 0. i

